balaglitazone and Body-Weight

Agonists of Perioxisome Proliferator-Activator Receptor gamma (PPARgamma), which work as insulin sensitizers, are approved for type 2 diabetes. However, adverse effects, such as oedemas, infarctions, and increased fracture rates, limit their applicability. We performed a head-to-head comparison of equipotent glucose lowering concentrations of the partial PPARgamma agonist balaglitazone and the full agonist pioglitazone in male diet-induced obese rats, to investigate effects on bone formation, fluid retention and fat accumulation. Sixty male dio induced obese rats were divided into five categories: vehicle, pioglitazone 10 mg/kg, pioglitazone 30 mg/kg, balaglitazone 5 mg/kg, balaglitazone 10 mg/kg. At day -7, 21 and 42 fasting serum samples were collected and whole body tissue composition was evaluated by MR scanning. Food intake and bodyweights were monitored during the study period. At day 42, an oral glucose tolerance test was performed to evaluate glucose homeostasis in the rats. During oral glucose tolerance test both pioglitazone and balaglitazone lowered baseline glucose and maintained the suppression during the oral glucose tolerance test. Both lowered basal insulin, peak insulin secretion and total insulin during oral glucose tolerance test. Both drugs increased bodyweight, although this was more pronounced in the pioglitazone 30 group. MR scans of body fat and water showed that all treatment groups increased their fat mass, whereas only the pioglitazone 30 group accumulated water. Pioglitazone treatment led to reduction of the bone formation marker osteocalcin, whereas balaglitazone treatment did not affect it. Balaglitazone is a novel PPARgamma agonist, which potently lowers glucose levels, while it neither affects fluid retention nor bone formation parameters.

Topics: Adipogenesis; Animals; Biomarkers; Blood Glucose; Body Weight; Bone and Bones; Bone Resorption; Diet; Glucose Tolerance Test; Hypoglycemic Agents; Lipid Metabolism; Magnetic Resonance Imaging; Male; Muscles; Obesity; Osteogenesis; Pioglitazone; PPAR alpha; Quinazolines; Rats; Thiazolidinediones; Water

Balaglitazone is a novel thiazolidinedione in clinical development for the treatment of type 2 diabetes. Common side effects associated with PPARgamma receptor agonists are weight gain, oedema and adipogenesis. Balaglitazone is a selective partial PPARgamma agonist and it has been speculated that such compounds have a more favourable safety margin than full agonists. We have compared impact of equi-efficacious antihyperglycaemic doses of balaglitazone with full PPARgamma agonist rosiglitazone on body fluid accumulation, cardiac enlargement, and adipogenesis. Equi-efficacious antihyperglycaemic doses (ED(90)) of balaglitazone (3 mg/kg/day) and rosiglitazone (6 mg/kg/day) were determined in male diabetic db/db mice. In adult male rats treated for up to 42 days, feeding, drinking, anthropometry, and plasma volumes were measured. Total plasma volume was measured with dye dilution technique. Compared to vehicle, rosiglitazone consistently increased food intake throughout the 42 day treatment period. In contrast, balaglitazone increased food intake in the last week of the experiment. However, both rosiglitazone and balaglitazone increased water intake. After 42 days, rosiglitazone treated rats displayed significantly elevated adiposity. Rosiglitazone increased total blood and plasma volumes throughout the treatment. Twenty-one days of balaglitazone treatment had no significant impact on blood or plasma volumes, whilst 42 days of balaglitazone increased plasma volume but to a significantly lesser extent than seen for rosiglitazone (vehicle: 46.1+/-1.5; balaglitazone: 50.8+/-1.21; rosiglitazone: 54.6+/-1.6 ml/kg). Heart weight was significantly elevated only in rosiglitazone treated animals. At doses inducing comparable antihyperglycaemic control, the full PPARgamma agonist, rosiglitazone, induces more pronounced body fluid retention and heart enlargement than seen for the partial PPARgamma agonist, balaglitazone. Thus, partial agonists may pose safer alternative to current anti-diabetic therapy with full PPARgamma agonist.

Topics: Adipogenesis; Adipose Tissue; Animals; Blood Volume; Body Weight; Drinking; Eating; Heart; Humans; Hypoglycemic Agents; Male; Mice; Organ Size; PPAR gamma; Quinazolines; Rats; Rosiglitazone; Thiazolidinediones